The present invention relates to an inspection apparatus, with which the high working efficiency can be attained and which has the flexibility for the layout modification of an assembly line.
When an industrial product is manufactured and brought on the market, quality inspection has been performed generally for the product in the middle or at the end of the production/assembly line in order that the stable quality of the product may be maintained. In a manufacturing plant of magnetic tape cartridge, inspection is performed for a tape cartridge to check whether or not it satisfies the requirements specified by the standards and those internal by the manufacturer.
The conventional quality inspection has been performed on a step by step basis by a man or an inspection apparatus each time a product reaches some manufacturing or assembly stage which allows it to undergo an inspection. For example, the inspection for the normal operation of a moving part has been conducted in such a manner that an inspector manually moves the moving part or the load required for the operation is checked if it lies within a given range of values by an inspection apparatus after the completion of the moving part assembly. When plural inspections are conducted, the subsequent inspection with one inspection unit is performed in series after the completion of an inspection with another inspection unit.
A dedicated inspection unit has been required for each inspection, when the subsequent inspection is performed in series after the completion of an inspection. Fixing and positioning of a product have been required for each inspection before starting it with an inspection unit. Therefore, there has been the problem that the facility costs increase in terms of the inspection units and their space, and the inspections require a large amount of time as well.
The layout of an assembly line requires modifications depending on the production output and the product specification. Conventionally, when the assembly line has plural inspection units, each of them has requested reinstallation in order to accommodate the modifications. As the inspection units require the measurement accuracy generally, the readjustment peculiar to an inspection unitxe2x80x94checking of the parallelism, the output and othersxe2x80x94is necessary, when the inspection unit is moved. It is therefore troublesome to reinstall and readjust the inspection units each time the layout of the assembly line is modified, which is an obstacle to improve a product and raise the productivity.
The object of the present invention to assess the problems mentioned above is to provide an inspection apparatus which enables the speed-up and high efficiency of inspection as well as the flexibility to the modification of an assembly line.
The present invention provides an inspection apparatus, which is directly connected to an assembly line and employed for inspections of a work after assembly, comprising: an arrival platform to which the work after assembly is carried in; an inspection table on which the work is inspected; a departure platform from which the work after inspection is carried out; a transfer unit for moving the work which has completed inspections on the inspection table to the departure platform as well as moving the work carried in to the arrival platform to the inspection table; and a fixture for fixing the work moved to the inspection table while inspecting the work, wherein a plurality of inspections are performed in parallel while the work is fixed on the inspection table.
As the requirements of plural inspections for a magnetic tape cartridge in conformity with the LTO (Linear Tape Open) standard, included are four inspections: (a) write protect operation inspection for measuring the force to open or close the inadvertent erasing protector, (b) door opening force inspection for measuring the force to open the sliding door, (c) reel lock release force inspection for measuring the force to release the reel lock mechanism and (d) leader pin/spring contact inspection to check the contact between the leader pin spring and the leader pin. Among these inspection requirements, at least two inspections would be preferably performed in parallel. It goes without saying that another inspection may be added.
This type of inspection apparatus performs the plural inspections in parallel while a workxe2x80x94moved from the arrival platform by a transfer unitxe2x80x94is fixed by a fixture on the inspection table. Fixing of the work conducted for each inspection conventionally can be combined to one operation and the inspections are performed in parallel as well. The inspection apparatus thus enables the reduction in time required for the inspections.
The flatness inspection of the cartridge case, which is for measuring the flatness of the base plate of the cartridge case, would be preferably performed at either of the following steps: before fixing of the work by the fixture after the transfer unit brings the work of magnetic tape cartridge to the inspection table or after releasing of the work by the fixture following the completion of the inspections. The reason for it is that the flatness inspection of the cartridge case must be performed while it is not fixed.
Thus the inspections for the magnetic tape cartridge can be speeded up more.
The present inspection apparatus can accommodate flexibly the layout modification of the assembly line, since all required is to move and place only the inspection apparatus so that the arrival platform may be directly connected to the assembly line, and perform leveling and adjustment for only the particular inspection apparatus. Apparently it looks like easy to conduct two inspections in parallel, though it has not been brought into practice conventionally. The present invention enables the parallel inspection, thereby improving the efficiency of a production system.
Performing inspections in parallel does not strictly means that the start and finish of one inspection coincide with those of the other. It includes that one inspection is started before the completion of the other inspection overlapping some portions of respective inspections.